Continuous laminating machine



April 15, 1958 A. E. cRANs'roN, JR., :nu 2,830,631

CONTINUOUS LAMINATING MACHINE AprilV 15, y1958 Af.' E. cRANs-roN, JR.,ErAL 2,830,631

CONTINUOUS LAMINATINGAMCHINE Filed July 6, 1954 4 Sheets-Sheet 2 ALBERTE. cRANsToN JR. `:EssE A. wAssER ATTRNEYs .April 15, 1958 A.'E.cRANsroN, JR., Erm. 2,830,631

commons LAMINATING MACHINE Filed July s. 1954 4 sheets-sheet s IHHI IHHI

INVENTORS A RT E. CRANSETON JR.

JE E A. WASS R ATTORNEYS April 1s, 195s A.' E. (.ZRANESTON,n JR., ETALCONTINUOUS LAMINATING MACHINE 4 Sheets-Sheet 4 Filed July 6, 1954 kan. JY N MOR S MNE Y NNs E EAS m VRA O Ncw T I T LA A .ME E. @E AJ Y B UnitedStates Patent O CUNTlNUUUS LAMINATING MACHINE Albert E. Cranston, Jr.,Oak Grove, and Jesse A., Wasser, Milwaukie, Qreg.

Application `lnly 6, 1954, Serial No. 441,206

Claims. (Cl. 144-28l) prising the number of veneers desired inthefinished panels, such as three, iive, seven or more. Each such pile ofglue coated Veneers is then inserted in one of the interplaten spaces ofa multiple platen hot press. Such a press is adapted to pressand cureten to -twenty panels at one time, the press-being` opened at thetermination of the presscycle for removal of all the completed panelsand the insertion of `a newload of veneer assemblies which have beenprepared for the next cycle of operation. This is known as a batch typeof operation, and it isused extensively for making rigid panels ofstandard size which are necessarily limitedby the dimensions -ofthepress platens, such as four feet by eight feet.'` The operation involvesa great deal of manual handlingof theveneers in4 laying up theassembliesvpriortopressingand also manual handling of therhotfpanelswhich must be removed from t the press after :each cycle of operation;kOther disadh vantages of the conventional batch processiare theloss ofheat whiletthe press is open for unloading and loading, the` longinterval between vglue spreadingyand tpressing, f limitation ofpanelasize, and the-cyclical interruptions to a steady, continuous workflow in the handling of thet materials going into the, press and the`handling of finished panels produced by the. press.

Also, the conventional. hot press. used. for` laminating is madeasrigidfasapossible, entailing a very expensive type ofeconstruction.which supplies. all the pressure exerted by the press is mounted oni-arelatively small number of vertical pistons operableinhydraulicvcylinders extending down into wells beneath the press. Inorder to apply uniform pressure over the whole area of the material inthe press the lower platen is made `of `a single rigid steel plate ofsome thicknessbacked up -by heavy I-beams which transmit and distributethe pressure lapplied by the hydraulic pistons tothe extremities of theplaten. This great mass must be lifted each time thepress is closed, anda considerable amount of energy is consumed in each cycle of operationin just lifting the movable platens to closed position.

ln addition to the numerous disadvantages pointed out, the conventionaltype-of rigid and ponderous movable press platen is found to beunsatisfactory for making relatively thin laminate sheets such as asingle layer of wood veneer between two layers of paper. Whereas a.press load of veneers, such as are involved in the manufacture ofplywood, is sufrcientlyresilient and compressible to adjust itself`readily to small variations in the spacing of the` platens, a single:thin laminatesheet is incapable of Ordinarily, the lowermost platen2,830,631 Patented pr. 15, 1958 ice .d such self-compensation.Regardless of the rigidity of the press and the precision with which'the parts are made, there inevitably exists in a press `four feet wideand eighty feet long a variation in the spacing of the upper and lowerplatens from point to point which is sufficient to concentratesubstantially the entire pressure of the press in certain local areas,leavingvother areas substantially without-any application of pressure,or, at least, insufticient pressure. Previous attempts to correct thefault by making the movable platen still heavier and `more rigid" havebeen unsuccessful because the samedefect resultsfrom slight variationsin the veneerthickness even if the press is geometrically perfect.Conventional hot presses' are generally considered to be incapable of'laminating thin materials, such as paper and wood veneer, in a three#ply assembly.

The general objects of the present invention are, therefore, to providea novel form of `hot press which will over` come the shortcomings anddisadvantages of conventional hot presses in the manufacture of lthinlaminate sheets.

More specific objects are to provide `a hot press which willsuccessfully laminate thin materials in a continuous strip of anydesired length, to provide a hot press having a light weight andrelatively flexible movable platen, to provide a pneumatically operatedhot press, to provide a hot press of the type described having a verybrief operating cycle so as not to interpose long delays in the workflow to and from the press, to provide a hot press apparatus which willmaterially reduce manual handling of the material, to produce a hotpress apparatus which is largely automatic and continuous in operation,to provide' a control mechanism for hot press apparatus of the typedescribed which will time the press cycle `and perform a number ofoperations in sequence with a minimum of supervision by the operator,and to provide an improved hot press apparatus which is relativelyinexpensive to build and economical and reliable in operation.

The present apparatus comprises, in general, a lay-up table, atwo-platen hot press, a feed mechanism, a clipper knife and an electricand pneumatic control system. The function of the apparatus is tolaminate a single thin layer of wood veneer between two layers of paper,plastic sheet material, metal foil, or any other sheet material capableof being adhesively. united with the surfaces of wood veneer. It is notnecessary that the same type of sheet material be used on both sides ofthe veneer, as, for example, when metal foil is applied to one side itis often desirable to have paper applied to the other side. For thepurpose of describing the method and apparatus, it will be assumed thatthe sheet material on both sides of the veneer layer is paper.

The veneer sheets are first coated on both sides with a Y suitableadhesive and are then laid up edge to edge as core s strips between thetwo paper face sheets which may be fed f During the pressing cycle oneof the platens is moved toward the other to press the assemblage andapply the necessary heat to cure the adhesive and form a hat, smooth,ilexible, composite sheet. The process is continuous in the sense that afinished portion of the corn posite sheet is delivered intermittently atshort intervals from one side of the press while a length of laid upassen bly is continuously being prepared on the other side of the press.

A pair of horizontal feed rolls grip the composite sheet which emergesfrom the outlet side of the press and draws all the material forward therequired distance in each feed movement at the end of a heating cycle.Thus, the alternate operation of the press and feed rolls discharges acontinuous ribbon of the composite sheet which may be split lengthwiseinto a plurality of ribbons of the desired width. These ribbons are fedthrough a transverse clipper knife for cutting into the desired lengths.Suitable automatic mechanism is provided for controlling the opening andclosing of the press, the length of feed movement, the operation of theclipper knife, and for cycling these operations.

An important feature of the press is the flexible construction of one ofthe platens which is designed to apply uniform pressure over the wholearea of the material which is in contact with the other platen which isrigid. The applied pressure is not affected by irregularities orvariations n the thickness of the material which is interposed betweenthe two platens. Preferably, the lower platen is made flexible andupward pressure is applied under the whole area of the lower platen bymeans of a relatively large number of closely spaced pneumatic diaphragmunits which are distributed across the breadth and length of the lowerplaten.

. The foregoing and additional objects and advantages will becomeapparent as the description proceeds in connection with the accompanyingdrawings illustrating a preferred embodiment of the invention. It is tobe understood, however, that various changes and modifications may bemade and certain features may be used without others Without departingfrom the spirit of the invention as defined in the appended claims.

In the drawings:

Figure 1 is a plan View of the apparatus of the invention;

Figure 2 is a s'ide elevation view of the apparatus shown in Figure 1;

Figure 3 is a cross sectional view of the press, taken on the line 3 3of Figure 2;

Figure 4 is an elevation view of the valve mechanism controlling themovements of the lower platen, taken on the line 4 4 of Figure 2;

Figure 5 is a plan view of the valve mechanism shown in Figure 4;

Figure 6 is a top plan view of the lower platen with portions brokenaway to illustrate the construction thereof;

Figure 7 is a fragmentary view of the feed switch and clipper switchactuating mechanism, taken on the line 7 7 of Figure 2;

Figure 8 is a sectional view taken on the line 8 8 of Figure 2 showingthe longitudinal shearing rolls; and

Figure 9 is a schematic wiring diagram of the control system for thevarious operating units of the machine.

In Figures 1 and 2, the apparatus is seen to comprise, essentially, alay-up table A at one side of the press B, a feed roll mechanism C atthe other side of the press, and a clipper mechanism D beyond the feedroll. The veneer core strips are laid up by hand on the table A and theassemblage including the face sheets is drawn by the feed roll mechanismC in intermittent step by step movement through the press B. Thefinished laminate product issues in a continuous ribbon from the feedroll mechanism C until it is cut into the desired lengths by theoperation of clipper D.

The table A extends some distance to the left of the portion shown inFigures 1 and 2 and is equipped with a paper roll support (not shown)for feeding a lower sheet of paper 10 in a continuous strip across thesurface of the table. Glue coated veneer core strips 11 are placed onthe sheet 10, and, as the sheet 19 and core strips 11 are drawn into thepress, a top sheet of paper 12 is applied over the assemblage as it isdrawn from an upper paper roll 13.

The frame of the press B comprises a pair of longitudinal stringers 15surmounted by a plurality of transverse I-beams 16. Resting on thetransverse I-beams 16 are three longitudinal I-beams 17 supporting aplurality of pneumatic diaphragm units 1S. The diaphragm units 18 areequipped with short cylindrical struts or supporting columns 19 for alower platen 20.

An upper platen 21 is rigidly mounted on a plurality of longitudinalI-beams 22 connected with transverse beams 23, as shown in Figure 3.Transverse beams 23 are supported at their ends on standards 24 whichare connected with the lower transverse beams 16. A pair of upperlongitudinal frame members 25 interconnect the standards 24 and supporta shaft 26 for the upper paper roll 13. The ends of shaft 26 areequipped with sleeve bearings 27 which are adapted to rest on pairs ofrollers 28 on the upper frame members 25 to facilitate free turningmovement of the paper roll.

The work engaging surface of the lower platen cornprises a plurality oflong narrow steel plates 30 disposed in edge to edge relation, as shownin Figures 3 and 6. The work engaging surface of the stationary upperplaten comprises a plurality of similar plates 31 rigidly connected witha plurality of spaced transverse plates 32 which are connected with thelongitudinal I-beams 22. The lower platen plates 30 rest on and areconnected with spaced transverse plates 33. Electric heating units 35are mounted in heat conducting relation with the platen plates 30 and 31in the spaces between the aforementioned supporting plates 32 and 33.Suitable thermal insulation, not shown, covers the'plates 32 and 33 andthe heating elements. The lower platen is flexible to some extent inboth longitudinal and transverse directions and any tendency to warpingis confined to the relatively narrow widths of the plates 30. The plates30 and 31 are not directly connected to each other.

The pneumatic diaphragm units 18 each comprise a rigid bottom shell orhousing member 40 having a flat bottom surface adapted to rest on theflat upper surface of an I-beam 17. A flexible diaphragm 41 is securedaround its rim to a peripheral ange edge of the housing 40 to form aclosed pressure chamber 42 wherein the dia. phragm 41 s adapted to movevertically, like a piston, in response to variations in pneumaticpressure in the chamber 42 beneath the diaphragm. 'Ihe main central areaof the diaphragm 41 is reinforced by a circular metal plate 43 whichsupports the cylindrical struts 19. The upward thrust of each strut 19is distributed over a plurality of the spaced plates 33 by a square capplate 45, as best shown in Figure 6. An upper housing part 46 protectsthe diaphragm 41 and has a large central opening to allow free verticalmovement of the strut 19. The struts 19 have portions cut away on theupper and lower ends thereof to form offset feet 47 for engaging thediaphragm plate 43 and a cap plate 45. This arrangement providesventilation for cooling the struts and lengthens the heat conductingpaths between cap plate and diaphragm plate 43 so that the high platentemperature will not be transmitted directly to the diaphragm material.

Referring now to Figures 4 and 5, the several diaphragm chambers 42 areconnected with three manifold pipes 50 equipped with individual valves51 to turn on and shut olf air pressure from supply pipes 52. Each valveis operated by a lever 53 which has an angular movement not exceedingdegrees between open and closed limit positions. The three valve levers53 are connected together for movement in unison by a common link 54Which has one end pivotally connected with a piston rod 55 in an aircylinder 56. One end of the cylinder 56 is pivotally connected at 57with a supporting bracket 58 on the frame of the press.

Cylinder 56 is of the double acting type having two pipe connections 61and 62 with a conventional solenoid valve unit 63. The solenoid valveunit 63 has two coils for shifting a balanced spool valve member (notshown) to one orthe other of two limit positions. In one limit positionthe valve admits air pressure from a supply pipe 64 to one of the supplypipes 61, 62 to move the piston rod 5S and valve levers 53 to the olf orclosed position. At such time the other of the two pipes 61, 62 isconnected by the spool valve memberwith anexhaust port 65 in the housingof the solenoid valve. In .its other limit position, the spool valvemember reverses the connectionsbetween pipes 61, 62 and the supply andexhaust pipes 64, 65 to move piston rod 55 in the opposite direction andshift valve levers 53 to open position.

When valve levers 53 are in closed position, the pressure in supplypipes 52 is shut olf from manifold pipes 50 and the latter are connectedwith exhaust ports 66 to relieve the pressure Ain all the diaphragmchambers 42. When the pressure is thus reduced to atmospheric value, theweight of the lower platen depresses the diaphragms 41, causing thepress to open. When the valve handles 53 are in open position, exhaustports 66 are closed and supply pipes 52 are connected with manifoldpipes 50 to establish sufficient pressure in diaphragm chambers 42 tolift the diaphragms 41 and close the press. In addition to supplyingmerely the pressure necessary to raise the lower platen to close thepress, the pressure in diaphragm chambers 42 exerts sufficientadditional upward force against the lower platen to press the top andbottom sheets of paper and 12 against the opposite faces of core strips11 to eifect a strong permanent bond at the platen temperature which ismaintained by heating units 35. By reason of its flexibility, the lowerplaten adjusts itself to irregularities in the thickness of the work andapplies uniform pressure over the whole area of the platen.

The feed roll mechanism C and clipper D are mounted on a frame 70 whichmay be bolted to the frame of the press B. The frame 70 includes a pairof standards 71 supporting a transverse beam 72. The standards 71 alsohave bearings for the-shafts 73 and 74 of `longitudinal shearing cutters75. These are rotary type cutters which trim olf the rough edges andsplit the completed ribbon laminate into a plurality of parallel ribbonsof the desired widths.

Another pair of standards 76 is equipped with bearings to support theshafts 77 of a pair of feed rolls 78. The laminate material is supportedin its passage through the trimming cutters 75 and feed rolls 78 by atransversely ilat surface 79 having a longitudinal arch 8i) between thefeed rolls and the clipper D. The function of the arch Si) is tofacilitate the upward buckling of the material during the brief intervalwhile its forward movement is arrested by the operation of the clipperknife. This prevents excessive crowding of the material against theclipper blade which might otherwise cause bindingand interfere with atrue and straight transverse cut.

The clipper D is of conventional construction, being of the type used tocut wood veneer. The movable blade is normally raised to allow thematerial to pass thereunder, and is actuated at the proper time by apiston rod 83 in a pneumatic cylinder 81 acting through a conventionaltoggle linkage S2.

The lower trimming cutter shaft 74 and lower feed roll shaft 77 arerotated by suitable drive mechanism from the electric motor 85,indicated diagrammatically in Figure 9. The upper trimming cuttershaft73 is gear driven from the lower shaft 74 and the upper feed rollis simi larly driven by the lower feed roll. Cutter shafts 73 and 74 aredriven at a speed which will rotate the cutting rolls 75 slightly fasterthan the material is pulled ahead by the feed rolls 78.

Control system The lower feed roll shaft 77 carries a small gear 86,Figure 7, which drives a larger metering gear 87 equipped with a :switchactuating pin 8S. As shown in Figure 2, a feed switch 90 is mounted onthe frame 70 adjacent the metering gear 37 in a position to be actuatedby the pin 8S once in each revolution of the metering gear 87. Feedmotor 85 is deenergized by such actuation of the switch 90,1but themomentum of the drive mechanism carries the pint` 97 out ofengagementwith the switch 100 after the motor is deenergized whereby the switch90- alwaysreadjacent its periphery. One or more switch actuating4 pins97 may be inserted in the apertures 96. Metering wheel rides on and isfrictionally drivenby a drive cone 9K mounted on a threaded end of theupper `feed roll shaft 77. By shifting cone 98 arially-on its supportingshaft 77 the wheel 95 may be brought toV bear on different diameterportions of the cone as shown inFigure 7 to vary the driving ratio.`Cone 98 is securedin adjusted position by la jam nut 99. Mounted on thearmiA 92 adjacent the metering wheel 95 is a'cli-pper switchltli)v in aposition to be actuated by the pin or pins 97.

A Iplaten switch 101 is mounted on the frame of the machine in aposition to be actuated by a lug 89 on the lower platen 20, as shown inFigure 2. The operating mechanism of this switch is arranged so that theswitch is lnot operated when the lower platen is raised. When the pressopens, the descending movement of the lower platen 211 causes the switch101 to be momentarily closed and then reopened.

A number of manual control switches are mounted on the frame of themachine adjacent the table A as shown in -Figure 2. There is a toggle-switch 102 which is in the nature of a main switch, a feed stop switch103, and a press close switch 1114 which will also stop the feedmechanism. The numeral 105 designates a jogging switch to operate thefeed mechanism momentarily when desired.

The numerals 1696 designate adjustable thermostatic control-s for theplaten heating units 55, whereby the platen temperatures may bemaintained at certain predetermined constant values.

Figure 9 illustrates the electric and pneumatic control system foropening and closing the press B, starting and .stopping the feed rollmechanism C and operating the clipper D. The heating circuits for platenheating unitsy 35 are controlled exclusively by the thermostatic means106 and are not shown in Figure 9. The feed motor 85 is energized from apower circuit 109 and the control system is energized from the supplywires 11), 111. The power circuit for motor 85 is controlled by a feedrelay havinga solenoid coil 112 and an armature 113 which is lifted toclose the motor circuit when the relay is energized. At such times, afourth contact bar 114 is held in engagement with a pair of stationarycontacts 115, 116. When the relay is deenergized, the armature 113 fallsto the position shown, opening the motor circuit. For convenience, thisand the other relays in the system will be referred to generally by thenumerals applied to their solenoid coils.

Contact 115 is connected with a wire 117 leading to a stationary contact118 `which is normally engaged by the switch arm 1211 in feed switch9i). A second stationary contact 121 is momentarily engaged by theswitch arm 1211 during the time that switch actuating member 122 isengaged by the moving pin 5S on metering gear 87. An internal spring,not shown, in the switch 90 always returns the movable switch arm intoenga-gement with the contact 118 after pin 88 leaves engagement withactuating member 122 and motor 85 and gear 87 come to rest. Contact arm120 is connected by a wire 123 with the supply wire'111.

The push button switches 1133 and 104 are spring returned to the normalpositions shown. A wire 125 connects solenoid coil 112 with a stationarycontact 126 in the :switch 164 which has a second stationary contact 127in the same circuit. Contact 127 is connected with a contact 123 in theswitch 103 which has a second stationary contact 129. Contact 129 isconnected with the terminal 139 of toggle switch 102. The other terminal131 of the toggle switch is connected with the line wire rl`he free endof arm 92 110. Switch 104 also has a stationary contact 132 connectedwith line wire 111 and a contact 133 connected with a wire 134.

The push button switch is normally spring biased to its open positionshown. A stationary contact is connected with wire 125 and a stationarycontact 136 is connected with line wire 1 10. A third stationary contact137 is connected with a wire 138 and a fourth sta tionary contact 139 isconnected with a wire 140 leading to the line wire 111. The wire 138 isalso connected with relay solenoid terminal 116 and the terminal 141 ofplaten switch 101. The other terminal of switch 101 is connected with awire 142 leading to the line wire 111.

Wire 134 is connected with contact 121 in feed switch 90 and also withone terminal of the solenoid .coil 145 of a valve control relay for theair supply to lift the lower platen. This relay :solenoid circuit iscompleted through a wire 146 connected with terminal 130 of toggleswitch 102. The relay has an armature 147 equipped with a lcontact bar148 normally engaging a pair of stationary contacts 149 and 150 when therelay is deenergized. Contact 149 is connected with a wire 151 andcontact 150 is connected with the wire 146. When the relay is energizedthe contact bar 148 engages a pair of contacts 152 and 153. Contact 152is connected with a wire 154 and contact 153 is connected with the wire146. The numeral 155 designates diagrammatically a dash pot mechanism orother time delay device to hold the relay armature in raised positionfor an interval of time necessary for a pressing operation. layedopening relay which may be adjusted Within the desired limits to holdthe armature up after solenoid coil 145 has been deenergized.

The solenoid valve 63 in Figures 5 and 9 has a pair of opposed solenoidcoils 156 and 157 connected with the respective wires 154 and 151. Acommon wire 158 connects the two coils with line wire 111. When the coil156 is energized the solenoid valve 63 admits air to the proper end ofcylinder 56 in Figure 5 to open the valves 51 and raise the lower platen20, and when the coil 157 is energized the solenoid valve 63 admits airto the other end of cylinder 56 to close the valves 51 and exhaust theair in diaphragm chambers 18 through ports 66 to atmosphere to lower theplaten 20 and open the press.

Clipper switch 100 has a movable contact arm 160 connected through wire161 with line wire 111 and a stationary contact 162 connected through awire 163 with one terminal of solenoid coil 165 of a clipper relay.Contact arm remains in open circuit position until actuating member 159is engaged by pin 97 on metering wheel 95. The other terminal of relaycoil is connected with wire 146. This clipper relay has an armature 166equipped with a contact bar 167 and a delayed opening device 168. Whenthis relay is energized the contact bar 167 engages a pair of stationarycontacts 169 and 170. The delay device 168 holds the contact bar 167 inengagement with contacts 169 and 170 for a sucient time to allow theclipper to operate once and then the'contact bar is dropped back intoopen circuit position.

The clipper cylinder 81 is a double acting cylinder having air pressuresupply pipes 171 and 172 connected with the opposite ends thereof toreciprocate the piston rod 83 in opposite directions in successivecutting strokes. The pipes 171 and 172 are connected with a solenoidvalve 175 which is in turn connected with an air pressure supply pipe176. The valve device 175 contains a balanced spool valve which isshifted between two limit positions by a pair of opposed solenoid coils177 and 178. When coil 178 is energized, the valve connects pipe 172with pressure supply pipe 176 and when coil 177 is energized, the pipe171 is connected with pressure.

A wire 1'79 connects the two coils with relay contacts 169. Therespective coils are connected individually with a pair of stationarycontacts 180 and 181 in a pressure switch, designated generally by thenumeral 182. Sta- This is a conventional type of def hausted toatmosphere through valve ports 66,

tionary contacts 183 and 184 in the pressure switch are connected withline wire 111. A contact bar 185 is connected with a ilexible diaphragm186 in a diaphragm chamber 187. A spring 188 normally deflects thediaphragm inwardly and holds the contact bar 185 in engagement withcontacts 180 and 183. A pipe 186 connects diaphragm chamber 182 with thepipe 172 whereby when pressure is admitted to this pipe the diaphragm186 is deected outwardly, causing the contact bar 185 to engage theother pair of contacts 181 and 184. The switch device 182 thereby actsas a reversing switch for the solenoid valve 175 to admit air toopposite ends of the cylinder 81 in successive clipping operations.

Operation ln starting up the machine the lower and upper face sheets 10and 12 are rst pulled through the open press by hand and engaged betweenthe feed rolls 78. Glue coated core strips 11 are then laid up on thetable A on top of the lower sheet 10. As shown in Figure l, the operatorfirst places the core strips 11 on the paper 10 and then straightens andaligns them and pushes them into edge abutting relation in preparationfor the rst cycle of the machine.

In Figure 9 the various switches and relays are shown in their normalrest positions when the machine is shut down with all circuitsdeenergized. When the material is ready for operation of the machine,the operator rst switches on the heating units 35 and closes toggleswitch 102. This produces no immediate function but serves to preparecertain circuts for the initial phase of operation. The energization ofplaten valve coil 157 merely continues to hold the press open. To startthe machine, the operator presses push button switch 104, closing acircuit from line wire 111 through wire 134, relay solenoid 145, Wire146, and toggle switch 182 back to line wire 110. This circuit raisesthe armature of press relay 145, and after push button 104 is releasedthe delay device 155 holds the armature 147 in raised position withcontact bar 148 in engagement with contacts 152 and 153 until the end ofthe interval for which the device 155 is set. A circuit is therebyclosedthrough line Wire 110, toggle switch 102, wire 146, contact bar148, wire 154, solenoid valve coil 156, and wire 158, back to line wire111. This produces operation of solenoid valve 63 to admit air pressureto the proper end of cylinder 56 in Figures 4 and 5 to open the valves51 and admit air pressure to the manifold pipes 50 leading to all thediaphragm chambers 18 beneath the lower platen 20.

The lower platen is thereby raised and the press held closed until timedelay device 155 releases the relay armature 147 to allow it to returnto the normal position shown. The dropping of armature 147 breaks thecircuit through solenoid valve coil 156 and energizes solenoid valvecoil 157 by a circuit through a line wire 110, toggle switch 102, wire146, contact bar 148, wire 151, coil 157, and wire 158, back to linewire 111. The energizing of solenoid valve coil 157 shifts the spoolvalve member in the valve unit 63 to reverse the air supply connectionsto cylinder 56, moving piston rod 55 in a direction opposite to itsprevious movement and closing the valves 51. When the valves 51 are thusclosed, the supply pressure from pipes 52 is cut olf and the pressure indiaphragm chambers 18 and manifold pipes 50 is exallowing the lowerplaten 20 to fall and open the press.

The closing of the press brought lug 89 into engagement with theoperator of switch 101, but the switch mechanism is arranged so that noswitch movement is produced by such engagement. However, when the pressopens, the disengagement of lug 89 from the switch operator (Figure 2)causes switch 101 to close, completing a circuit through line wire 111,wire 142, switch 101, wire 138, relay solenoid coil 112, wire 125, pushbutton switch 104, pushbutton switch 103, and toggle switch 102, back tothe line Wire 110. This circuit energizes feed relay 112, lifting thearmature 113 and closingn the power circuit from supply wires 109 tothefeed motor 85. The operating mechanism (not shown) for switch 101 isarranged to cause this switch to be closed momentarily and then reopenedduring the descending movement of lower platen 20, whereby switch 101immediately returns to its open position shown in Figure 9. However, thelifting of relay armature 113 completes a holding circuit for the relaythrough wire 123, contact arm 120 of switch 90, wire 117, and contactbar 114 in parallel with the reopened platen switch 101. This holdingcircuit maintains the energization of the feed motor after platen switch101 reopens.

Motor 85, thus energized by the opening of the press, drives the feedrolls 78 to pull a length 'of the material through the press and push itthrough the clipper D. By reason of the holding circuit just described,this feed movement continues until pin 88l on gear 87 engages theoperating lever 122 of feed switch 9) to shift the contact arm 120 outof engagement with contact 118 and into engagement with contact 121.Disengagement of contact arm 1Z0 from contact 118 breaks the holdingcircuit for relay 112, allowing the armature 113 to drop and deenergizefeed motor 85. After the motor 85 has been deenergized, the momentum ofthe feed drive mechanism carries the pin 83 out of engagement withswitch actuating lever 122, allowing contact arm 120 to be returned by aswitch spring (not shown) to'its normal engagement with contact 118.However, the holding circuit for relay 112 has now been opened by thedropping of contact bar 114, so the return movement of switch arm 120 atthis time is of no effect and the feed mechanism remains stationary. j

The metered operation of feed rolls 78 hasjhus pulled the pressed lengthof material out of the press and has pulled in a new length of materialincluding glue spread core strips 11 which have been laid up on thetable A during the Vpressing interval. When contact arm 120 in feedswitch 9i) engages the contact 121, a circuit is completed from linewire 111 through wire 123, contact arm 120, wire 134, and platen relay145 to wire 146, toggle switch 102, and line wire 110. This circuitenergizes platen relay 1@5 which lifts its armature 147 to bring Contactbar 14d into engagement with contacts 152 and 153. After contact arm 120leaves engagement with contact 121, this circuit is broken but thearmature 147 is held in raised position for the duration of anotherpressing interval by the action of the delayed opening device Thelifting of contact bar'148 again cornpletes a circuit through thesolenoid coil 156 of solenoid valve 63 to effect operation of the pistonrod 55 and valves 51 in Figures 4 and 5 as previouslydescribed,admitting air to the diaphragm chambers 18 and closing the press foranother press cycle. The press and feed cycles thus repeat in sequenceuntil the machine is stopped by the operator.

lf toggle switch 102 is opened during feed movement, the feed relay 112is deenergized to stop the feed motor 85. lf toggle switch 102 is openedduring a press interval, both solenoid valve coils 156 and 157 aredeenergized, but this does not result in the closing of valves 51 toopen the press because the balanced spool valve member in solenoid valve63 remains in its last position supplying air pressure to the end ofcylinder 56 which opens the valves 51. Switch 102 is not used foremergency stop purposes.

Push button switch 103 serves as an emergency stop for the feed motor Sin case the core strips 11 become disarranged on the lay-up table A orin case the operator does not have a suicient number of core strips inposition to occupy the length of the press, or for any other reason whenit may be desired to stop the feed movement. The feed motor isre-started by pressing switch 104. Switch 103 does not affect thecontrols for thev4 press.

Push button switch 104 stops the feed and closes the press. This switchis also used as a starting switch in the manner hereinabove described.

Push button switch 105 is referred to as ajogging switch. For example,in setting up the machine for operation, after the upper and lowersheets 10 and 12 have been drawn through the press, the ends of thesesheets may be inserted in the nip of the feed rolls 78 and the joggingswitch touched momentarily to rotate the feed relis sufficiently to gripthe paper. This is done while the main toggle switch 102 is open,whereby the feed relay 112 is closed and feed motor 85 is energized onlyso long as the switch 105 is held closed. The jogswitch 105 therebypermits operation of the feed rolls for a long or short interval, as maybe desired, without putting the machine in its normal cycle of operationsubject to the other automatic control devices.

It will be observed that the holding circuit through con-- 163, clipperrelay solenoid coil 165, wire 146, switch` 102, and supply wire 110. Theenergization of clipper relay raises its contact bar 167 into engagementwith contacts 169 and 170 to complete a circuit from wire 146 throughwire 179 and one or the other of the valve solenoid coils 177 or 178 asdetermined by the position of the contact bar 165 of pressure switch182. When lcontact bar 185 engages the upper contacts 180 and 183, thesolenoid coil is energized to supply pressure to the pipe 172 andretract the piston rod 33 to operate the clipper mechanism. Theadmission of pressure to pipe 172 operates the pressure switch 180 todeenergize the circuit for solenoid coil 178 and prepare a circuit i forsolenoid coil 177 to produce an opposite movement of piston rod 83 whenthe clipper switch 100 and relay 165are next operated. lt was previouslyexplained that the clipper is operated by a toggle mechanism whereby thecutting blade makes onestroke when the piston rod 83 moves outwardly andanother stroke when the piston rod moves inwardly.

In order to prevent repeated operations of the clipper if the pin 97should come to rest in engagement with the operating lever 159 ofclipper switch 100 at the end of a feed movement, the clipper relay 165is equipped with a delay device 16S which causes the armature 166 to bereleased promptly after momentary closing of the relay contacts, eventhough the relay coil 165 may still be energized by the closed positionof switch arm 160.

A wide variety of suitable glues are available on the market. The gluemay be either of the cold setting or hot setting type, according to thespeed desired in the pressing operation. Urea resin glues are preferred.

The temperature and pressing time are governed by the nature of thematerials used. A thermal gradient exists through the thickness of theface sheets 10 and 12 whereby in a short press interval the temperatureat the glue line may be considerably lower than the platen temperature,depending upon the thickness and heat conductivity of the sheets 10 and12. When the sheets 10 and 12 are paper, a platen temperature of 450 F.been used successfully with a pressing interval of l0 to l5 seconds. Thefeed movement requires yabout live seconds, thereby allowing threepresses per minute. In an eight-foot press, this rate of operationproduces 24 linear feet of laminate product per minute. It is notnecessary that the press interval be long enough to dry the gluecompletely, as it will continue to dry and set after leaving the press.The foregoing values of time, temperature and dimension are merelyillustrative and are not intended to limit the invention.

Thus, the present machine is fully automatic in its press, feed andclipping operations, producing continuous ribbons of laminate productwhich are automatically clipped to any desired length. The press cycleis fast enough to permit a substantially continuous work ilow as fast asa workman can lay up the core strips on the bottom continuous face sheet10. It is not necessary to assemble a great amount of material for asingle press load, and it is not necessary to incur a larger investmentin a battery of presses to achieve a substantially continuous work ow.Also, there is considerable advantage in the very short interval of timetranspiring between the spreading of the glue on the core strips and thepressing operation, as this permits the use of an inexpensive coldsetting glue of a grade which cannot be used in a conventional multipleplaten hot press because of the necessarily relatively long interval oftime between the glue spread operation and the pressing operation.

Having now described our invention and in what manner the same may beused, what we claim as new and desire to protect by Letters Patent is:

1. A hot press for laminating sheet materials comprising a rigidhorizontal platen, a flexible horizontal platen, and a plurality ofpneumatic diaphragm units operatively connected with said flexibleplaten for vertical movement, the work engaging surface of said exibleplaten comprising a plurality of flat plates disposed in edge abuttingrelation, a plurality of elongated narrow members connected with saidplates, and a plurality of thrust means each extending across aplurality of said members and connecting said members with saiddiaphragm units.

2. A hot press for laminating sheet materials comprising a rigidhorizontal platen, a flexible horizontal platen, and a plurality ofpneumatic diaphragm units operatively connected with said flexibleplaten for vertical movement, the work engaging surface of said ilexibleplaten comprising a plurality of Hat-plates disposed in edge abuttingrelation, a plurality of spaced members supporting said plates, heatingunits disposed in the spaces between said members, apertured tubularstruts on said diaphragm units, and an individual thrust 'plate on eachof said tubular struts engaging a plurality of said members.

3. A hot press for laminating sheet materials comprising a rigidhorizontal upper platen, a lower platen support comprising ya pluralityof longitudinal beams, a plurality of pneumatic diaphragm units seatedon each of said beams, a ventilated tubular strut on each diaphragmunit, an individual thrust plate on cach of said struts, -a plurality ofspaced transverse plates supported by said thrust plates, a plurality oflongitudinal plates supported on said transverse plates and disposed inside by side edge abutting relation, and heating units mounted in thespaces between said transverse plates, said plates and heating unitsconstituting a exible lower platen for the press.

4. Apparatus for laminating sheet materials comprising a hot presshaving a movable platen, means for moving said platen to open and closethe press, feed rolls for moving said materials through the press, meansfor driving said feed rolls, a feed control relay connected with saiddriving means, a platen control relay connected with said platen movingmeans, a control member rotatably driven by said feed rolls, a switchconnected with both of said relays and actuated by rotation of saidcontrol member to operate said relays to stop said driving means andclose the press, means to operate said platen control relay to open thepress, and a switch actuated by opening movement of said platen tooperate said feed control relay to start said driving means.

5. Apparatus for laminating sheet materials comprising a hot presshaving a movable platen, fluid pressure operated means for moving saidplaten to open and close the press, feed rolls for moving said materialsthrough the press, an electrical motor for driving said feed rolls, afeed control relay controlling the energization of said motor, a platencontrol relay and solenoid valve controlling said fluid pressure means,a control member ro tatably driven by said feed rolls, a switchcontrolling both of said relays and actuated by rotation of said controlmember to operate said relays to stop said motor and close the press,means to operate said platen control relay after -a pressing interval toopen the press, and a switch actuated by opening movement of said platento operate said feed control relay to start said motor.

References Cited in the tile of this patent UNITED STATES PATENTS395,592 Schwarzler Jan. 1, 1889 808,756 Johnson Jan. 2, 1906 856,416McLarty June l1, 1907 1,702,185 Weber Feb. 12, 1929 2,050,191 LiebowitzAug. 4, 1936 2,172,002 Stanley Sept. 5, 1939 2,254,394 Ratley Sept. 2,1941 2,373,770 Martin Apr. 17, 1945 Y 2,407,070 Frame Sept. 3, 19462,547,157 Gibbons Apr. 3, 1951 2,570,926 Elmendorf Oct. 9, 19512,672,835 Paul Mar. 23, 1954 2,684,626 Eberle July 27, 1954

